1. Statement of the Technical Field
The inventive arrangements relate to cryptographic systems having ring generators. More particularly, the inventive arrangements relate to a cryptographic system comprising a ring generator configured for performing a mixed radix conversion absent of unwanted statistical artifacts.
2. Description of the Related Art
Many number theoretic based computational systems include ring generators. A ring generator is a simple structure over a finite field that exhaustively produces possible outputs through repeated mapping. The mapping is some combination of an additive and a multiplicative mapping, with irreducible polynomials being ideal. For example, a ring generator includes repeated computations of an irreducible polynomial f(x)=3x3+3x2+x on the finite Galois field, GF[11]. A finite or Galois field GF[M] is a field that contains only a finite number of elements {0, 1, 2, . . . , M−1}. The finite or Galois field GF[M] has a finite field size defined by the Galois characteristic M. M is most often chosen to be either a power of two (2) or an odd prime.
Despite the advantages of such a ring generator, it suffers from certain drawbacks. For example, the odd-sized ring generator's reliance on the Galois characteristic M is computationally inefficient in a digital (binary) domain. Also, lookup table operations performed in the finite or Galois field GF[M] are resource intensive. Moreover, the ring generator's orbits are highly deterministic. As such, knowledge of a mapping and current finite field conditions gives complete knowledge of an output sequence and in many applications it is desirable to mask this information. Such applications include, but are not limited to, a cryptographic application.
In view of the forgoing, there remains a need for a ring generator implementing an arithmetic operation that is computationally efficient in a digital (binary) domain. There is also a need for a ring generator having an implementation that is less hardware intensive than conventional ring generator implementations. There is further a need for a ring generator having orbits that are more robust in obscuring their deterministic characteristics for use in a cryptographic system.